Thallus effuse, lead- to pale-grey, c. 0.15 mm thick, areolate; areoles irregular, flat to slightly concave, 0.5-0.7 mm across, separated by deep cracks; cortical cells c 4-5 µm across with brown (K—, N—) and blue-black (K—, N+ red) pigments, often more strongly pigmented at the edge of the areoles; epinecral layer 15-20 µm thick often present in paler areas; prothallus absent. Medulla I—; aeruginose pigment (K—, N+ red) present in the lower medulla Photobiont chlorococcoid, cells globose 10-14 µm diam.
Apothecia frequent, orbicular, lecideine, black, arising from the areoles, 1(2-3)/areole, initially immersed with concave disc, becoming slightly sessile with flat, roughened disc and scarcely raised margin when mature, (0.2-)0.25-0.3(-0.4) mm diam., margin 0.02 µm wide. Excipulum thin and poorly developed, internally hyaline, cortical cells swollen (to 5µm) with dark blue black and brown pigments (K—, N+ red). Hypothecium hyaline, 20-30 µm thick, composed of randomly orientated hyphae. Hymenium hyaline, I+ blue, 65-70 µm thick; epihymenial zone 5-10 µm thick, blue black (K—, N+ red), comprising the pigmented upper portion of the paraphyses. Paraphyses simple or very sparingly branched, 1.5-3.0 µm wide, septate, cells 5-7µm long, apices swollen to 5.0 µm with blue-black (K—, N+ red) pigmented caps, separating in water and KOH. Asci cylindrical, c. 50 x 17 µm, Catillaria-type. Ascospores hyaline, 1(-2) septate, 10-12 x 4-6 µm.
Conidiomata not observed.
Chemistry: no substances detected by TLC.
Distribution: Known only from the type locality of coastal limestone rocks on Campbell Ilsland (NZ) and one locality on the Falkland Islands.
Notes: Imshaug referred all his collections of crustose species with lecideine apothecia and 1-septate, hyaline ascospores to Catillaria. Many of these collections are better placed in Halecania, Megalaria (see below) or Toninia, but C. glaucogrisea has all the characters of Catillaria s. str.
Catillaria glaucogrisea is similar to the British Isles endemic species C. subviridis (Nyl.) Zahlbr. However, Killias (1981) gives the habitat of C. subviridis as siliceous rocks, the pigmentation of the epihymenium as dark brown, and ascospore dimensions as 10-16 x 5-6 µm. He also includes a photograph of the holotype showing a poorly developed thallus, and apothecia with an extremely thick, proper margin. In comparison, C. glaucogrisea occurs on limestone, has a blue-black epihymenium, ascospores measuring 10-12 x 4-6 µm, a well-developed, continuous thallus, and apothecia with a narrow margin.
The Campbell Island collections occurs on hard limestone as small patches in a mosaic of other crustose species (e.g. Caloplaca sp. Rinodina sp, Toninia sp., and Verrucaria sp.). Imshaug gave the collection form the Falkland Islands the herbarium name Catillaria "immersa" but, although it is on sandstone, it is identical to C. glaucogrisea in morphology and apothecial anatomy.
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